Only 3 out of 4 Gig RAM

  john bunyan 17:29 21 Nov 2009

is usable. I recently installed W7 64 bit in a dual boot with XP Pro. I have installed a total of 4 gig ram, but in the "System info" it says 4 Gig installed, 3.00 usable. I have a NVidia 7800 GTX ( 256kb memory) video card also. My Motherboard is a MSI K8N SLI-F, and I have a 2.2 gigahertz AMD Athlon 64 X2 Dual core. Theoretical max RAM on motherboard is 4 Gig. Any ideas how I can get the system to use the 4 Gig? Tried max -ing the setting in msconfig ,boot, advanced - no effect.

  john bunyan 17:31 21 Nov 2009

Should have added the above is in the W7 64 gig boot - I realise there is a 3 Gig limit with XP

  User-312386 21:54 21 Nov 2009

Surely you mean 3.25gb is useable? If so then you have to go into memory mapping in the BIOS and change it, i have a socket 939 DFI lan party and i cant find memory mapping so i am stuffed really

Good luck in finding it!

  john bunyan 21:19 22 Nov 2009

No, it says 4 Gig installed,3.0 gig usable. I thought it would, in 64 bit W7, show the installed 4 plus the video card'd 256 Kb. Will keep trying! Dont know why motherboard's spec says it will support 4 gig RAM, and W7 64 bit should be able to use it... Maybe someone else can help? Thanks for your input.

  jimv7 10:53 23 Nov 2009

I think you will find that because of the dual boot, windows xp is in charge and only allowing 3gb+graphic card, a clean install with windows 7 will cure the problem.

  [email protected] 11:35 23 Nov 2009

Is XP and W7 on the same HDD?
If so this may be the problem as jimv7 points out.

  john bunyan 15:27 23 Nov 2009

Thanks very much. I could not get a dual boot on master and slave to work, so I now have 3 partitions, one for W7, one for XP and a third for data. I usually , after usual virus scans etc and a defrag, clone the primary to the slave once a week, and do an image of each drive to an external HD as well, using ATI 2010. I am reasonably happy to get rid of XP now, so would it work to format that partition, as a clean reinstall is a hassle to reinstall dpwnloads etc, de register Photoshop etc.

  WaTcHiNg 15:44 23 Nov 2009

I have raised a similar issue in the Helproom forum. My ASUS P5VD2-X shows 4096MB installed and 2495MB usable.

I have no dual boot and have W7 64bit installed so I'm not entirely sure how whatever OS you install could affect what your BIOS tells you is installed. The BIOS runs before the OS starts surely?

  sonyboy 15:52 23 Nov 2009

Dual boot or Multi boot can cause the issue you have experienced ass the other guys' have said...I have just cured an issue with Memory mapping and getting full utilization of memory in 64 Bit mode myself !
After managing my remaining partitions with Acronis ...It kept "screwing " the MBR and throwing up "Boot loader " issues..I had a Multi boot setup running Windows7 ...Vista and XP...even though I decided to finally "ditch" XP ...It was the old XP partition that was on a seperate hard drive that eventually turned out to be the culprit.
After deleting XP from the partition ..I had to go into BIOS and select the Boot order screen re assign the hard disks and duly select the Hard disk that contained my Windows7! After that ...everything ran just fine..Multi boot setups can be handy..but sometimes they can throw a wobbler !

  john bunyan 16:48 23 Nov 2009

Hi sonyboy! As usual, you are a guru!I will shortly get rid of XP and follow your advice. I have another problem re Twain and W7 64 bit but will post another thread. By the way with your and others advice , on W7 I installed PC Tools as Firewall, Avira as anti virus and so far SAS, and C Cleaner Will Add Malawarebytes soon.JB

This thread is now locked and can not be replied to.

Elsewhere on IDG sites

Best Amazon Echo: What’s the best Alexa speaker?

Kano Computer Kit Complete review: A fun DIY 'laptop' that teaches kids to code

Best pro photo editors for Mac 2018

TV & streaming : comment regarder les Jeux olympiques d’hiver 2018 ?